The present invention relates to an abrasive machine, in particular a grinder for removal of material from an envelope surface of a substantially cylindrical work piece, the machine comprising a rotatably driven tool.
Abrasive machines such as grinding machines, lapping machines, honing machines, milling machines, etc., are known in many slightly different designs and embodiments. It is desirous that the machine be compact and as space-saving as possible. For obtaining good machining results, it is on the other hand important that the co-operating parts of the machine have a high mutual stiffness and low tendencies of vibration. These last-mentioned properties are often obtained by giving the machine a heavy bedding and a sturdy and robust design, and therefore these two requirements are often contradictory to the desires for compactness and space-saving properties.
It is known from Swedish Patent Application Nos 9702587-8 and 9702588-6 to provide abrasive machines which at least partially fulfil the above properties. In both said applications, a machine is provided which comprises a tubular cylindrical housing having a longitudinal cylindrical inner space. The cylindrical inner space has a longitudinal axis which is offset from the longitudinal axis of the housing. A shaft is arranged for angular displacement in the cylindrical inner space and has a recess accommodating a motor which is coupled to a rotatable work head. The work head together with the chucking equipment is arranged to hold and rotate a work piece to be treated. The housing is enclosed by a rotatably driven outer casing, with the casing being firmly connected to a lid member having an opening forming at its inner edge a tool, such as a grinding wheel. When the shaft is angularly displaced, the work head is displaced with the work piece in a path allowing the work piece to approach and contact the inner periphery of the tool.
The construction of the machines disclosed in said patent applications implies that the work piece and the tool are supported in a very stable manner since only very short distances are present between the work piece and the shaft which supports the work piece. Furthermore, the arrangement of the tool along the inner periphery of the lid member also implies that the tool exhibits high stability. As a result, these machines exhibit superior precision compared to conventional machines having long support shafts which are subject to vibration and thermal effects.
The machines according to said Swedish patent applications are designed to be able to grind the outer and inner envelope surfaces respectively of annular work pieces which can be gripped by conventional chucking equipment. A need exists, however, for a machine which is capable of removing material from an envelope surface of substantially cylindrical work pieces, for example rollers for bearings, which cannot reasonably be gripped by conventional chucking equipment.
This object is achieved by means of a machine in particular a grinder for removal of material from an envelope surface of a substantially cylindrical work piece, said machine comprising:
a tubular cylindrical housing extending about a longitudinal axis, said housing having a longitudinal cylindrical inner space extending from a first end of said housing, said cylindrical inner space having a longitudinal axis which is offset from the longitudinal axis of said housing;
a shaft arranged in said inner space for angular displacement therein, said shaft being provided with a recess;
a motor arranged in said recess;
a spindle coupled to said motor, said spindle carrying a first rotatably driven tool;
a rotatable outer casing peripherally enclosing said tubular cylindrical housing;
a lid member associated with said outer casing for co-rotation therewith, said lid member extending radially over a region of said first end of said tubular cylindrical housing with said lid member being provided with a central through opening having a peripheral surface;
a second rotatably driven tool disposed on said peripheral surface of said central through opening of said lid member, and
support means for holding said work piece between said first and second rotatably driven tools;
wherein said shaft is arranged in said inner space such that when said shaft executes an angular displacement in said inner space, said first rotatably driven tool is caused to effect a radial displacement relative said second rotatably driven tool.
Preferred embodiments of the invention are detailed in the dependent claims.